Infinite cold must correspond to a finite number of degrees of the air-thermometer below zero; since, if we push the strict principle of graduation sufficiently far, we should arrive at a point corresponding to the volume of air being reduced to nothing, which would be marked as -273° of the scale (-100/.366, if .366 be the coefficient of expansion); and therefore -273° of the air-thermometer is a point which cannot be reached at any finite temperature, however low [Absolute Zero].

Kelvin[1848]

2.

The entropy change of a system during a reversible isothermal process tends towards zero when the thermodynamic temperature of the system tends towards zero [Nernst 'principle'].

Nernst[1906]

3.

The maximum work obtainable from a process can be calculated from the heat evolved at temperatures close to absolute zero [Heat Theorem].

Nernst[1906]

4.

The absolute value of the entropy of a pure solid or a pure liquid approaches zero at 0 K.

Planck[1911]

5.

It is impossible to reach absolute zero in a finite number of operations.[Nernst ‘statement’]

Nernst[1912]

6.

If the entropy of each element is some crystalline state be taken as zero at the absolute zero of temperature, every substance has a finite positive entropy; but at the absolute zero of temperature the entropy may become zero, and does so become in the case of perfect crystalline substances.

Lewis & Randall[1923]

7.

The contribution to the entropy of a system by each aspect which is in internal thermodynamic equilibrium tends to zero as the temperature tends to zero.

Simon[1931]

8.

The entropy of every system at absolute zero can always be taken equal to zero.

Fermi[1936]

9.

The absolute zero temperature cannot be reached; a consequence of Nernst’s heat theorem.

Bazarov[1964]

10.

The addition of thermal energy to a substance generally increases its temperature and its entropy; the removal of thermal energy from a substance generally decreases its temperature and its entropy; hence, at absolute zero, the entropy of a perfect crystal, regardless of its chemical composition, may be taken as zero.

Bent[1965]

11.

The entropy of a perfect crystal of any element or compound at absolute zero temperature is zero.

Lehninger[1971]

12.

It is impossible to reduce the temperature of any system or part of a system to the absolute zero in a finite number of operations.

Adkins[1983]

13.

The entropies of substances at 0 K can be assigned the value of zero.

Barrow[1988]

14.

The entropy of all pure substances in thermodynamic equilibrium approaches zero as the temperature of the substance approaches absolute zero
[Nernst theorem].

Black & Hartley[1996]

15.

The entropy change for isothermal processes at absolute zero of temperature is zero.

Wark & Richards[1999]

16.

No process can lead to T = O K in a finite number of steps.
[unattainablility form]